The Dutch National Institute for Public Health and the Environment, RIVM has described building blocks for a definition of microplastics. Considerations as regards criteria and threshold values serve as input for discussion at EU European Union (European Union) level.

To facilitate a quick and cost-effective screening of microplastics RIVM proposes a decision scheme. Confirmation of microplastic identity is obtained in 5 steps.

Five properties

Point of departure for the definition is the broad understanding in environmental science about the general properties of microplastics. The starting point for further refinement is therefore the following description: microplastics are synthetic materials, and consist of solid particles that are smaller than 5 mm. Additionally, microplastics are insoluble in water and not degradable.

If legal or voluntary measures to reduce the emission of microplastics are to be implemented, a definition of microplastics is necessary. A definition provides legal clarity and enables the consistent monitoring of trends in microplastic pollution and the transparent evaluation of effects of policy measures.